Casting machine



A. L. WILKES CASTING MAQHINE March 25, 1930.

Filed April 50, 1928 Patented Mar. 25, 1930 UNITED STATES ALFRED L.WILKES, F LOS ANGELES, CALIFORNIA c'AsgING MACHINE Application led April30,

x Ihis invention has to dowith a casting machine, andit is a generalobject of the invent1on to provide an improved, effective and practicalmachine operable to cast material at spredetermined temperatures.

The machine provided by this invention is particularly suited forcasting metals or al- -loys in cases where definite casting temperaturesare important. For example, the machine is especially suited to castinggold 0r gold alloys such as are used in dentistry.

For the purpose of facilitating an understanding ofa simple form andapplication of the invention, I will refer to it as it is related-to thecasting of gold and gold alloys for dental purposes,'it being understoodthat such reference is not to be construed as limiting the broaderprinciples of the invention.

In the making of gold or gold alloy parts for dental purposes it iscustomaryto prepare a mold or impression of the part to be formed andthen cast the metal into the mold. Various types of apparatus have Vbeendevised for use in makingv such castings, it having been found that thecentrifugal type of casting machine is well suited to this class ofwork.y The molds are usually made of plaster, the impression beinglformed by embedding a wax, or similar image of the object, 1n theplaster to be burned out after the plaster has set. Several grades ofgold and different gold alloys have have been developed for dental use,it having been found that different grades of gold or various goldalloys of gold have various characteristicsand that some are bettersuited for certain purposes than others. It is also true that a givengold or gold alloy cast at different temperatures will have differentcharacteristics, there being an ideal casting point for each particularalloy or grade of gold.

It is an object of my present invention to provide a casting machine bywhich castings can be made at known temperatures, thus making itpossible to obtain uniform and correct castings.

It is another object of this invention to provide a casting machine ofthe character mentioned which is suitable for practical or 50 generaluse and is simple to operate.

-be obtained.

1928. Serial No. 273,980.

A further object of the invention is to provide a casting machine of thecharacter mentioned, arranged and constructed so "that the exacttemperature of the'molten metal can The various objects and features ofmy invention will be best and more fully understood from the followingdetailed description of a typical form and application of the invention,throughout which description I refer to the accompanying drawings, inwhich:

Fig. 1 is a side elevation of a casting mav chine of the centrifugaltype embodying the present invention. Fig. 2 is a plan view of themachine being a view taken as indicated by line `.2--2 on Fig. 1. Fig. 3is a detailed sectional View taken as indicated by line 3-3 on Fig. 1showing a detailed construction that may be used in carrying out theinvention. Fig. 4 is an enlarged detailed sectional 70 view taken asindicated by line 4 4 on Fig. n. Fig. 5 is a diagrammatic vievTillustrating the electrical circuits included in the device.

yMy present invention provides, generally, a casting machine in whichthere is a cupola 10, a mold 11 in communication with the cupola toreceive molten metal therefrom, a thermo couple 12 located at or in the.cupola to be subject to the same -heat condltlons as the metal in thecupola, and an indicating instrument 13 electrically connected with thethermo couple 12.

In the present disclosure I have chosen to set forth a centrifugalcasting machine and therefore the cupola 10 is shown mounted on an arm14 projecting radially from a spindle or rotor 15 driven by a springmotor' 16, or the like.- The arm 14 and the cupola 10 with its connectedparts are counter balanced by 9o an arm 17 and a weight 18 which alsoserves as a handle by which the rotor lcan be conveniently turned towind the motor 16. 'Iohe motorl is provided with a suitablehouslng whichalso forms a base for the entire mao5 chine.

In the arrangement illustrated, the roter is'controlled by a lever 19pivotally mounted on the exterior of the motor housing. The controllever 19 is designed to cooperate with 100 a notch 20 in the peripheryof a iiange 21 projecting from the rotor. When the motor is wound thecontrol lever is engaged in the notch 2O where it will remain untiloperated in the direction indicated by the arrow in Fig. 2. When thecontrol lever is operated so that it is released from the notch therotor is released and is driven by the motor.

The cupola 10 may be of any suitable formation. For instance, it may bethe ordinary open type of cupola used in casting machines of thischaracter. In the drawings I have shown the cupola as comprising a metalcase 21a provided with a lining 22 of fire clay, or the like, shaped toform a cup-like depression A for carrying the metal to be cast. Thedepression A of the cupola is in communication with an opening 23 in thecase of the cupola, the opening 23 being provided to pass the moltenmetal when the machine is operated.

The mold 11 illustrated in the drawings is of a type commonly used inmaking castings for dental purposes and comprises a `metal case 24carrying a body 25 of plaster, or'the like, in which there is a cavityor opening B for forming the metal. Thecavity B in the mold is Vin opencommunication with the opening 23 in the casing of the cupola so thatthe molten metal passes directly from the cupola into the mold when themachine is operated.l In practice the mold is formed separate from thecupola and is releasably clamped in operating position through asuitable clamping device 26.

The thermo couple 12 provided by my invention is located in or at thecupola so that it is subject to the same heat conditions as the metal inthe depression Aof the cupola. In the preferred form of the invention,the thermo couple 12 is located Vin the bottom of thedepression A of thecupola and is, in fact, mounted to project into the depression A. `Ihave coated or protected the thermo couple with a body 30 of alundum sothat it is not oxidized or amalgamated with the metal in the cupola.Wires 3,1 and 32 extend from the thermo couple 12 through the lining 22'of the cupola. One of these wires is grounded, for instance is connectedto the rotor 15, or a suitable part of the machine, so that it isgrounded with the machine, while the other is maintained out ofelectrical connection `with the other parts of the machine.

The instrument 13 provided by my invention operates to indicate theelectrical condition of the circuit in'which the thermo couple isconnected. The indicating instrument 13 ispreferably located at a pointremote from the machine. With this arrangement one of the wires from'the thermo couple, for instance the wire 31fwhich is grounded to themachine, is connected with the instrument by a wire 318L which isconnected to the machine and extends to the instrument. The

other, or insulated wire 32 from the thermocouple, is connected to aninsulated contact ring 35 mounted on the'flange 21 of the rotor. A brush36 is mounted stationary on the motor case through suitable insulationand engages the ring to establish an electrical connection therewith. Awire 32a connects the brush 36 with the other terminal of the instrument13.

The instrument 13 may be of any suitable constructionk operable toindicate the electrical condition of the circuit in which the thermocouple is connected. The instrument preferably includes an indicatinghand 40 and a dial or scale 41 with 4which the hand cooperates to give areading of the electrical condition of the circuit, it being preferredthat the hand and scale cooperate to give such reading directly indegrees of temperature.

My present invention further provides an automatic control for the motoradapted to be set to release the motor when the metal in the cupola hasreached a predetermined temperature. In `the drawings I have illustratedan arrangement wherein there is an electromagnet 50 mounted on the motorcase and connected with the control lever 19. The winding of theelectromagnet is connected in a circuit carried by wires 51 and 52 andenergized' by suitable source of power, such as a battery 53. y Acontact device is connected inthe wire 51 at the instrument 13 to beoperated by the instrument. The contact device illustrated includes abody or carrier of insulating material havin two spaced cup depressions71 carrying bo les or globules 72 of mercury. The carrier 70 is mountedat the scale 41 of the' instrument so that the globules of mercury 72are in the path of the indicating hand 40. The globules of mercury areconnected in the line'51 so that the circuit is closed or completedthrough the indicating hand 40 when the hand is in contact with bothglobules of mercury. The carrier 70 is adjustably mounted so thatthe-circuit may be closed at the desired predetermined point ofoperation of the instrument. y

In the drawings I have shown the carrier mounted in a guideway 74extending parallel In the preferred construction, a guide or rest isprovided on the motor case, to clear or be out of the path of therevolving parts 'of the machine.v The rest may be used to support orguide a torch, or the like, that may be used in melting' the metal inthe cupola.

' Without the guide 80 an operator might have the torch in position tobe struck by the moving parts of the machine when the machineautomaticallyoperates. It is to be understood, of course, that themachine can be operated by the automatic control above described or canbe manually ope 'ated by the simple operation of the lever 19. f

Having described only a typical preferred,

form of my invention, I do not Wish to limit myseltl to the specificdetails set forth, but wish to reserve to myself any changes orvariations that may appear to those skilled in the art or fall withinthe scope of the followinlr claims.

Iaving described my invention, I claim:

l. In a'casting machine a receptacle for the material to he cast, a moldto receive the material, operating means for causing the material todischarge from the receptacle'to the mold, and a control for theoperating means whereby it operates upon the material reaching apredetermined temperature, the control including a thermo-couple at thereceptacle,

an ,electro-magnetic unit in connection with' the operating means and acontact device electrically connected to the thermo-couple and operableto cause encrgization of the unit. Y

2. In a casting machine a receptacle for the material to be cast, a moldto receive the material, operating means for causing the material todischarge from the receptacle to the mold including a motor for rotatingthe receptacle, and a control for the lnotor Whereby it operates uponthe material reaching a predetermined temperature, the controlincluding, a thermo-couple at the receptacle, an electro-magnetic unitto release the motor for operation, and a contact device electricallyconnected with the unit upon the material reaching a predeterminedtemperature.

3. In a casting machine a receptacle for the material to be cast, a moldto receive the ma.- lerial, operating means for causing the material todischarge from `the receptacle to the mold, including,vv a motor forrotating the receptacle, and a control for the motor Whereby it operatesupon the material reaching a predetermined temperature, the cont-rolincluding a thermo-couple, an indicating in- /strument electricallyTconnected with the thermo-couple, an electro-magnetic unit to releasethe motor, and a contact device operated by the instrument to engage theunit.

4. In a casting machine a receptacle for the material to be cast, a moldto receive the material, operating means for causing the material todischarge from the lreceptacle to the mold, including, amotor, andacontrol for the operating means whereby it operates upon the materialreaching a predetermined te1n.

pera-ture, the c ontrol including a thermo couple, an mdicatlnginstrument electrically connectedA with' the thermo-couple, anelectromagnetic unit to release the motor for operation, and anadjustable contact device operated by the instrument to energize theumt.

'5.' In a casting machine a receptacle for the material to be-cast, amold to receive the material, operating means for causing the materialto discharge from the receptacle to the mold, and a control for theoperating means whereby it operates upon the material reaching apredetermined temperature, the control including an electro-magneticunit in connection with the operating means, a thermo-couple at therecept-acle, an indicating instrument in circuit with the thermo-couple,anda contact devicev controlling the unit and operated by theinstrument.

6. In a casting machine a receptacle for the material to be cast, a moldto receive the material, operating means for causing the material todischarge from the receptacle to the mold by centrifugal action, and acontrol for the operating means -whereby it operates upon the materialreachinga predetermined telnperatule, including, a. thermo-couple at thereceptacle and an electro-magnetic unit electrically connected with thethermo-couple operable to release the operating means.

7. In a casting machine a receptacle for the material to be cast, a moldto receive the material, operating means for causing the material todischarge Jfrom thereceptacle to the mold, including a spring motoroperable to rotate the receptacle, and a control for the operating meanswhereby it operates upon the l material reaching a predeterminedtemperature, including, a thermo-couple at the receptacle, an indicatinginstrument electrically connected with the thermo-couple, anelectromagnetic unit operable to release the motor, and a contact devicecontrolling the unit and operated by the instrument.

In Witness that I claim the foregoing I have hereunto subscribed my namethis 24th day of April, 1928.

' ALFREDL. WILKES.

Aso

